The present invention relates to a semiconductor device, a semiconductor system, and a control method of a semiconductor device, and particularly to a semiconductor device, a semiconductor system, and a control method of a semiconductor device suitable for accurately monitoring the lowest operating voltage of a circuit to be monitored.
In recent years, in order to guarantee an operation of an internal circuit driven by a power supply voltage, a semiconductor system has been provided with a monitor circuit to monitor whether or not the power supply voltage has dropped below the lowest operating voltage of the internal circuit.
For example, Japanese Unexamined Patent Application Publication No. Hei 6(1994)-296125 discloses a configuration of accurately detecting a power supply voltage without a malfunction even at a low voltage by combining a power supply voltage detection circuit with a large variation and a low lowest-operating-voltage and a power supply voltage detection circuit with high accuracy and a high lowest-operating-voltage to each other.
In addiction, Japanese Unexamined Patent Application Publication No. Hei 8(1996)-274607 discloses a configuration of monitoring a power supply voltage by measuring a propagation delay period of time using a ring oscillator.